1. Field of the Invention
The present invention relates to isolated polypeptides having isoamylase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.
2. Description of the Related Art
Isoamylase is a debranching enzyme (E.C. 3.2.1.68) that hydrolyzes 1,6-alpha-linkages in amylopectin, glycogen, and beta-limit dextrins. Amylopectin is partially degraded by alpha-amylase which hydrolyzes the 1,4-alpha-glucosidic linkages into branched and linear oligosaccharides that results in the formation of alpha-limit dextrins. Unlike pullulanase, isoamylase has high activity towards amylopectin and glycogen and very low activity towards pullulan. Branched oligosaccharides can be hydrolyzed into linear oligosaccharides by debranching enzyme. The remaining linear oligosaccharides can be rapidly depolymerized to D-glucose by glucoamylase.
U.S. Pat. No. 4,335,208 discloses a process of saccharifying starch hydrolysate by an enzyme mixture of glucoamylase and an acidophilic isoamylase derived from Pseudomonas amyloderamosa. 
EP 1,002,062 concerns an isoamylase from Sulfolobus acidocaldarius and the use thereof in a starch conversion process.
WO 2005/121305 (Novozymes) concerns a process for production of beer having a low content of carbohydrates which comprises; a) preparing a mash in the presence of enzyme activities, b) filtering the mash to obtain a wort, and, c) fermenting said wort to obtain a beer, wherein the enzyme activities comprise; an alpha-amylase, a glucoamylase and an isoamylase.
It is an object of the present invention to provide polypeptides having isoamylase activity and polynucleotides encoding the polypeptides. The invention also provides uses of said isoamylase for syrup preparation and other related applications.